Just outside the village of Cherven, about 30km south of Ruse, are the remains of a remarkably intact 6th-century hilltop citadel. Several streets, towers and churches have also been discovered, and there are great views of the river valleys and peaks from the top. Wear comfortable walking shoes because it's a long climb up from the car park to the citadel.
Cherven was established in the 6th century by residents of Ruse who wanted to escape chronic barbarian invasions. The town became an important religious, economic and military centre during the Second Bulgarian Empire (1185–1396).
It's about a 45-minute drive south of Ruse, following Hwy 501 and watching for the turn-off for Cherven past Ivanovo. Infrequent public buses make the trip from Ruse's Iztok bus station (4 lv, one hr). Taxis from Ruse can take you there and back for 50 lv (including waiting time). Pack a lunch; Cherven has few services for visitors.